hbn
healthy building network
JUNE 2005
The Healthy Building Network’s
Guide to
Plastic Lumber
Brenda Platt, Tom Lent and Bill Walsh
A report by The Healthy Building Network. A project of the Institute for Local Self-Reliance
927 15th Street, NW, 4th Fl. — Washington, DC 20005 — www.healthybuilding.net
About the Institute for Local Self-Reliance
Since 1974, the Institute for Local Self-Reliance (ILSR) has advised citizens, activists, policymakers, and
entrepreneurs on how to design and implement state-of-the-art recycling technologies, policies, and programs
with a view to strengthening local economies. ILSR’s mission is to provide the conceptual framework, strategies,
and information to aid the creation of ecologically sound and economically equitable communities.
About the Healthy Building Network
A project of ILSR since 2000, the Healthy Building Network (HBN) is a network of national and grassroots
organizations dedicated to achieving environmental health and justice goals by transforming the building
materials market in order to decrease health impacts to occupants in the built environment – home, school and
workplace – while achieving global environmental preservation. HBN’s mission is to shift strategic markets in
the building and construction industry away from what we call worst in class building materials, and towards
healthier, commercially available alternatives that are competitively priced and equal or superior in performance.
Healthy Building Network
Institute for Local Self-Reliance
927 15th Street, NW, 4th Floor
Washington, DC 20005
phone (202) 898-1610
fax (202) 898-1612
general inquiries, e-mail: [email protected]
plastic lumber inquiries, e-mail: [email protected]
www.healthybuilding.net
Copyright © June 2005 by the Healthy Building Network. All rights reserved.
Table of Contents
ACKNOWLEDGMENTS
PREFACE
EXECUTIVE SUMMARY .................................................................................................................................... 1
MATERIALS USED ....................................................................................................................................................1
RECYCLED CONTENT ...............................................................................................................................................1
RECYCLABILITY ........................................................................................................................................................1
FINDINGS................................................................................................................................................................2
RECOMMENDATIONS ...................................................................................................................................... 3
INTRODUCTION ............................................................................................................................................... 4
GUIDE TO THE RATINGS ................................................................................................................................. 6
MOST ENVIRONMENTALLY PREFERABLE .....................................................................................................................6
ENVIRONMENTALLY PREFERABLE ...............................................................................................................................6
LESS ENVIRONMENTALLY PREFERABLE ........................................................................................................................6
NOT ENVIRONMENTALLY PREFERABLE EXCEPT FOR STRUCTURAL APPLICATIONS ............................................................6
NOT ENVIRONMENTALLY PREFERABLE: AVOID ............................................................................................................7
RATINGS .............................................................................................................................................................. 7
RATING CRITERIA AND FINDINGS ............................................................................................................. 10
I. MATERIALS USED ..............................................................................................................................................10
Polyethylene (HDPE and LDPE) ..................................................................................................................10
Polyvinyl Chloride (PVC) .............................................................................................................................12
Polystyrene (PS) ............................................................................................................................................12
Fiberglass .......................................................................................................................................................13
Findings.........................................................................................................................................................13
II. RECYCLED CONTENT ........................................................................................................................................14
Post-consumer vs. Post-industrial Recycled Plastic Content .........................................................................14
Findings.........................................................................................................................................................14
III. END-OF-LIFE RECYCLABILITY: A FACET OF SUSTAINABLE DESIGN ......................................................................15
Single Resins ..................................................................................................................................................16
Synthetic Composites ....................................................................................................................................16
Wood-Plastic Composites ..............................................................................................................................16
Findings.........................................................................................................................................................17
IV. STRUCTURAL LUMBER: THE EXCEPTION TO THE RULE.......................................................................................17
RECOMMENDATIONS .................................................................................................................................... 18
HOW TO CHOOSE ........................................................................................................................................... 19
CONCLUSIONS................................................................................................................................................. 20
RESOURCES ..................................................................................................................................................... 21
APPENDIX 1: PLASTIC LUMBER COMPANIES THAT DID NOT RESPOND
TO OUR INQUIRIES OR SURVEY .................................................................................................................. 22
APPENDIX 2: CONTACTS FOR PLASTIC LUMBER COMPANIES ............................................................. 23
END NOTES....................................................................................................................................................... 24
FIGURE 1: PLASTIC LUMBER PRODUCT RATINGS ..................................................................................... 8
FIGURE 2: PLASTICS USED IN PLASTIC LUMBER ..................................................................................... 11
Acknowledgments
We gratefully acknowledge all those who provided information for this report. Doug Rowe contributed to
the initial research. He developed our plastic lumber survey tool, gathered data via the Internet and phone
discussions, and compiled survey results. Twenty-three plastic lumber manufacturers and distributors took the
time to answer our questions and provide data on their products. Thanks for participating. We thank Mark
Gorrell, Ecology Center and Plastics Recycling Task Force, Berkeley, CA and Peter Anderson of RecycleWorlds
Consulting for their insightful review of the report. Thanks to Mark Rossi at Clean Production Action and Jamie
Harvie of the Institute for a Sustainable Future, for foundational research on chemical hazards and associated
health impacts of plastics production, use and disposal. Healthy Building Network staff members Paul Bogart,
Matthew Cacho, and Margie Kelly reviewed and improved the final version of this report. In addition, we
acknowledge our assistants Mark Wilger, Danielle Emmet, and Kira Gaza, who helped in many ways. Finally,
thanks to Kate Wharmby for editing the report and Oliver Seldman for its layout.
This report was made possible with the financial support of the Cedar Tree Foundation, Mitchell Kapor
Foundation, John Merck Fund, New York Community Trust, and the Kendeda Sustainability Fund of the
Tides Foundation.
All responsibility for the views expressed in this report or for any errors in it rests with the authors.
(Cover photo courtesy of the U.S. Army Corps of Engineers.)
Preface
The Healthy Building Network (HBN) published this report for two reasons. First, we want to assist consumers
interested in purchasing environmentally responsible plastic lumber products. Many who choose plastic lumber
are motivated by a desire to save forests or recycle plastic waste. Manufacturers often market their products to
appeal to these concerns. This study is the first to compare and evaluate plastic lumber products strictly from an
environmental and public health perspective.
We also want to positively influence the future direction
of the plastic lumber industry. The market for plastic
More than one-third of the
lumber is growing rapidly and the industry is very much
plastic lumber products
in flux. Manufacturers continue to experiment with
various materials and formulations in order to improve
considered are rated “Most
performance, reduce costs, and build new markets. As a
Environmentally Preferable.”
result, plastic lumber’s composition varies widely, from
100% post-consumer recycled content to 100% virgin
plastic resin. Some products are made with a single plastic resin, others use combinations of resins, and still
others combine other materials with plastic to make a composite. This report seeks to steer both manufacturers
and purchasers towards product formulations that are ecologically superior, and to reverse sales trends for the
most ecologically harmful products such as virgin polyvinyl chloride (PVC) plastic.
We know this can be done. In 2002 HBN initiated a consumer campaign that resulted in a negotiated agreement
to eliminate the use of the chromated copper arsenate (CCA) wood treatment formula from approximately 80%
of the annual $4 billion dollar pressure-treated wood market. This ended, as of January 2004, the nation’s largest
use of arsenic and the largest source of arsenic exposure to Americans. In another area, our close collaboration
with leading healthcare institutions to develop green building and procurement guidelines has already resulted in
the introduction of more than a dozen PVC-free alternative products.
Happily our research concludes that more than one-third of the plastic lumber products for which we have
information currently use material formulations that we rate “Most Environmentally Preferable” in this report.
This finding holds with it the prospect that the plastic lumber industry on the whole can be an important part of
a more sustainable economy.
Executive Summary
This Healthy Building Network report compares and evaluates different plastic lumber types from an
environmental and public health perspective, and offers advice on how to choose a plastic lumber product based
upon its health hazards and recycling impacts. We rate the environmental preferability of 38 plastic lumber
products manufactured by 30 companies based on three criteria:
1)
2)
3)
Materials used
Recycled content
Potential recyclability
No determination is made as to whether plastic lumber is on the whole either more or less preferable to other
materials with which it competes such as naturally rot-resistant wood, pressure-treated wood, steel, aluminum, or
concrete. Rather, this information is intended to inform those who are interested in understanding the range of
environmental and public health impacts associated with different plastic lumber products.
Materials Used
Most plastic lumber products on the market are made from polyethylene (commonly available in high and low
densities, HDPE and LDPE). Some manufacturers are also using polystyrene (PS) and polyvinyl chloride (PVC).
Still others rely on a commingled mix of different types of plastics (largely collected from municipal recycling
programs). All plastic types (also called plastic resins) currently used for lumber share a common origin in
fossil fuels and thus a common set of initial environmental and public health impacts. Plastics differ, however,
according to their manufacturing procedures and the additional materials used in formulating various products.
These differences distinguish some plastics as possessing greater chemical hazards than others throughout their
lifecycle of production, use, and disposal. While no plastic is environmentally benign, our analysis concludes that
the polyethylenes possess lesser chemical hazards and associated environmental health impacts, making them
environmentally preferable to those that have greater hazards and impacts such as PS and PVC.
To improve performance qualities such as rigidity or strength, some plastic lumber producers reinforce the
primary plastic resin with other materials. Fiberglass is one material often used to increase the load-bearing
capacity of plastic lumber. As fiberglass production and use raise significant health concerns, we rate fiberglassreinforced lumber products lower than fiberglass-free products. At least one company combines polystyrene
with HDPE for added strength. Because polystyrene’s lifecycle of production, use and disposal is associated with
greater chemical hazards, we give a lower rating to products containing this resin.
Recycled Content
Recycled content varies widely among plastic lumber products. Two-thirds of the products we review contain
post-consumer plastic content. We give the most credit to products that have a minimum 50% post-consumer
content. We give a lower rating to products that have less than 50% minimum post-consumer content.
Recyclability
In general, products that can be recycled after their intended use are environmentally preferable over those
that cannot. Recycling contributes to an overall reduction in resource consumption and pollution over time.
More than a dozen companies offer lumber made from a single resin, polyethylene, one of the most recyclable
and recycled plastics, while other plastic lumber products also contain other plastics, fiberglass, and/or wood
fiber or wood flour. Based upon the record of plastics recycling to date, these composite products will be more
difficult to recycle effectively than single resins. Therefore, we favor single-polyethylene-resin products as more
environmentally preferable over plastic composites or lumber made from commingled plastics.
1
Plastic Lumber Product Ratings
Findings
Ø
Most Environmentally Preferable: More
than one-third of the products (14 of 38)
we survey earn this designation. They use
only high- or low-density polyethylene and
contain high volumes (50% and greater) of
post-consumer recycled content.
Ø
Environmentally Preferable: Only
three products we survey combine high
percentages of post-consumer recycled
content with other plastics or wood fibers.
This designation acknowledges the high
post-consumer content but downgrades the
blending of different materials.
Ø
Less Environmentally Preferable: One
third of the products we survey (13 of
38) earn this designation. These include
mixtures of plastics and wood having low
(less than 50%) post-consumer recycled
content, and the HDPE-only products
with low, zero, or unknown post-consumer
recycled content.
Ø
Ø
Most Environmentally Preferable
Ameriwood (American Plastic Lumber)
BJM Industries
BreezeWood (Aeolian Enterprises)
Eco-Tech (Eco-Tech)
Eco-Tuff (Eco-Tech)
Enviro-Curb (Enviro-Curb Manufacturing)
Everlast (Everlast Plastic Lumber)
HDPE lumber (U.S. Plastic Lumber)
Leisure Deck (The Plastic Lumber Company)
MAXITUF (Resco Plastics)
Orcaboard (Durable Plastic Design)
Perma-Deck Advantage+ (Cascades)
PlasTEAK
Select (Bedford Technology)
Environmentally Preferable
Evergrain (Epoch Composite Products)
Perma-Deck Elegance (Cascades)
Northern Plastic Lumber
Less Environmentally Preferable
Bear Board (Engineered Plastic Systems)
ChoiceDek (A.E.R.T., Inc.)
CorrectDeck (Correct Building Products)
Evolve & Perma-Poly (Renew Plastics Division)
fiberon (Fiber Composites)
Four Seasons (Delmarva Industries)
Latitudes Decking (Universal Forest Products)
Monarch (Green Tree Composites)
Polywood nonstructural (Polywood)
Trex Origins (Trex)
Veranda (Universal Forest Products)
WeatherBest Select (Louisiana-Pacific)
WindRiver Fence (Aeolian Enterprises)
Not Environmentally Preferable Except
for Structural Applications: Four of the
products we survey are unique for their use
in demanding structural applications such
as bridge supports or railroad ties. These
products contain fiberglass or polystyrene,
materials associated with greater health
hazards during their lifecycle. Their use
may be justified for these applications;
otherwise avoid.
Not Environmentally Preferable Except for
Structural Applications
Ameriwood-Plus (American Plastic Lumber)
FiberForce (Bedford Technology)
Polywood (Polywood)
Trimax (U.S. Plastic Lumber)
Not Environmentally Preferable: Only
four of the products we survey earn this
designation. These include PVC and
polystyrene products that contain no postconsumer recycled plastic content. None of
the products in this category contain more
than 30% post-consumer plastic content.
Not Environmentally Preferable – Avoid
Boardwalk (CertainTeed)
eon (CPI Plastic Group)
Synboard (Synboard America)
Xpotential (XPotential Products)
Source: Healthy Building Network, 2005.
Note: Full chart is on page 8.
2
Recommendations
The Healthy Building Network endorses the following guidelines for plastic lumber purchases. These guidelines
are based on environmental, public health, and recycling considerations.
Ø
Favor products:
o with high recycled content, specifically high post-consumer recycled content.
o made from high-density and low-density polyethylene (HDPE and LDPE), recyclable resins
associated with fewer chemical hazards and impacts than other petroleum-based polymers.
o by producers sourcing resins from local municipal recycling programs, therefore cutting
transportation costs and supporting the local economy.
Ø
Limit use of:
o wood-plastic composites because of concerns about mixing biological and synthetic materials,
including limited end-of-life recyclability.
o fiberglass-reinforced or polystyrene-blended “structural” plastic lumber to demanding structural
applications such as railroad ties and bridge supports, as a less toxic alternative to chemically treated
wood.
o products with multiple commingled recycled consumer plastics as they will have more contaminants
and inconsistent properties. They also support token markets for plastics that otherwise are largely
unrecyclable, and many of which are highly toxic. This perpetuates the use of plastics that should be
phased out.
Ø
Avoid products made with:
o PVC and polystyrene because these are associated with more chemical hazards and impacts
throughout their lifecycle than other plastics.
o fiberglass for nonstructural applications that do not require reinforced plastic lumber (such as
decking boards, benches, and tables).
o predominantly non-recycled plastics. Alternatives with high recycled content are readily available.
3
Introduction
Plastic lumber is gaining market share in applications ranging from decking, retaining walls, and fencing to
park benches, tables, playground equipment, and landscaping products.1 Plastic lumber is generally perceived
as an environmentally friendly substitute to hardwoods from endangered forests, and a “non-toxic” alternative
to widely used pressure-treated wood, which contains copper and other chemicals.2 Plastic lumber is also
an important market for discarded consumer plastics, helping to divert valuable materials from landfill and
incinerator disposal. Product advertising often emphasizes these advantages. Product names such as EnviroCurb, Green Tree Composites, CorrectDeck, and Eco-Tech help brand the product as “green.”
All plastic lumber is not equal, however. The term “plastic lumber” encompasses a wide range of materials and
products. The type of plastics used, the amount of recycled content, recyclability of the end products, additives
and intended applications differ from product to product. Several authorities currently offer consumers advice
concerning the price and performance of plastic lumber products.3 This Healthy Building Network’s Guide to
Plastic Lumber is the first to compare and evaluate plastic lumber types and brands from an environmental and
public health perspective, and to offer buyers advice on how to choose a plastic lumber product based upon its
environmental, public health and recycling impacts.
This Guide evaluates plastic lumber
products based upon three criteria:
Materials Used: Most plastic lumber
products on the market are made from a
single resin, polyethylene, which is available
in high and low densities (HDPE and
LDPE). Some manufacturers are also using
polystyrene (PS) and polyvinyl chloride
(PVC). Still others rely on a commingled
mix of different types of plastics (largely
collected from municipal recycling
programs). All plastic types (also called
plastic resins) currently used for lumber
share a common origin in fossil fuels and
thus a common set of initial environmental
and public health impacts. Plastics differ,
however, according to their manufacturing
procedures and the additional materials
used in formulating various products.
These differences distinguish some plastics
as possessing greater chemical hazards
than others throughout their lifecycle of
production, use, and disposal. While no
plastic is environmentally benign, our
evaluation concludes that the polyethylenes
possess lesser chemical hazards and
associated environmental health impacts,
making them environmentally preferable to
those that have greater hazards and impacts
such as PS and PVC.
Plastic Lumber and Its Applications
Plastic lumber is a manufactured product generally rectangular
in cross-section and typically supplied in sizes corresponding to
traditional lumber. It may be solid or hollow and composed of
single or commingled resins or may be blended with wood or other
plant fibers. It is typically at least 50 percent by weight resin.
Plastic lumber appeared in the marketplace in the late
1980s. Since then, plastic lumber products have undergone
a series of developmental advancements that have
improved performance, reduced the price, and increased
availability. Early offerings had significant problems with
sagging and heat-induced warping. Engineering has greatly
increased the mechanical properties of current products.
A wide variety of products can be made with plastic lumber; most
represent outdoor applications:
Dimensional lumber
Planters & landscaping timbers
Decking
Trash can receptacles
Boardwalks & walkways
Playground equipment
Marine docks
Compost bins
Fencing & posts
Animal stalls
Picnic tables
Sound barriers
Benches
Parking stops
Bridges
Sign posts and signs
Retaining walls
Bicycle racks
Railroad ties
Truck sideboards
Pallets
Source: Healthy Building Network, 2005; and “ASTM
Specifies Plastic Lumber for Exterior Decking,” ASTM
Standardization News, Sept. 2001, available online at
http://www.astm.org/SNEWS/SEPTEMBER_2001/pllum_sept01.html.
4
To improve performance qualities such as rigidity or
strength, some plastic lumber producers reinforce the
primary plastic resin with other materials. Fiberglass is one
material often used to increase the load-bearing capacity of
plastic lumber. As fiberglass production and use have been
linked to pulmonary lung disease, affecting the lungs in a
manner similar to asbestos, we rate fiberglass-reinforced
lumber products lower than fiberglass-free products. At
least one company combines polystyrene with HDPE
for added strength. Because polystyrene’s lifecycle of production, use and disposal is associated with greater
chemical hazards, we give a lower rating to products containing this resin.
HBN’s Guide to Plastic Lumber is
the first to compare and evaluate
plastic lumber types and brands
from an environmental and
public health perspective.
Post-consumer Recycled Content: Recycled content varies widely among plastic lumber products. More than
two-thirds of the products we review contain post-consumer recycled plastic content. We give the most credit to
products that have a minimum 50% post-consumer content and a composition with high potential for end-oflife recyclability.
Potential Recyclability: Products that can be recycled after their intended use are environmentally preferable to
those that cannot. More than a dozen companies offer lumber made from a single resin, polyethylene, one of the
most recyclable and recycled plastics. However, many other plastic lumber products also contain other plastics,
fiberglass, or plant fiber. Based upon the record of plastics recycling to date, these composite products will be
more difficult to recycle than single resins. Therefore, we favor single-resin products as more environmentally
preferable over plastic composites or lumber made from commingled plastics.
5
Guide to the Ratings
Most Environmentally
Preferable
Favor products with high
post-consumer recycled
content and made from
recyclable resins that avoid
the environmental health
concerns of the worst resins
• Post-consumer recycled plastic
content 50% and greater
Environmentally
Preferable
Limit the use of
composite products
• Mostly plastic resins mixed with biological
materials, primarily wood fiber
Less Environmentally
Preferable
Limit the use of products
with low post-consumer
recycled content
• Post-consumer recycled plastic content
less than 50% or do not provide
data on post-consumer content
Not Environmentally
Preferable Except for
Structural Applications
Limit to demanding
structural applications
• Contain materials with high health impacts:
Not Environmentally
Preferable
Avoid – Environmental
and public health
hazard concern
• Contain materials with
highest health impact:
• Made from high-density and low-density
polyethylene, considered to have a
less toxic lifecycle than other resins
• More readily recyclable
• Questionable end-of-life recyclability
• Comparable products with higher postconsumer content are readily available
– fiberglass
– recycled polystyrene (PS)
– virgin PVC
– virgin polystyrene (PS), or
– shredded mixed automobile parts
(auto-shredder fluff), which contains
heavy metals and toxic fire retardants
Most Environmentally Preferable
More than one-third of the products (14 of 38) we survey earn the designation Most Environmentally Preferable
because they use only polyethylene and contain high volumes (50% and greater) of post-consumer content.
Environmentally Preferable
Only three products we survey combine high percentages of post-consumer recycled content with other plastics
or wood fibers. This designation acknowledges the high post-consumer content but downgrades the blending of
different materials.
Less Environmentally Preferable
One third of the products we survey (13 of 38) earn this designation. These include mixtures of plastics and
wood having low (less than 50%) post-consumer recycled content; the HDPE-only products with low, zero, or
unknown post-consumer recycled content; and one product that combines post-consumer polyethylene with
pre-consumer polystyrene.
Not Environmentally Preferable Except for Structural Applications
Four of the products we survey are unique for their use in demanding structural applications such as bridge
supports or railroad ties. These products contain fiberglass or polystyrene, materials associated with greater
health hazards during their lifecycle. Their use may be justified for these applications; otherwise avoid them.
6
Not Environmentally Preferable: Avoid
Only four of the products we survey earn this designation. These include products made from PVC, polystyrene,
and plastics recovered from shredding automobiles. This auto-shredder fluff is often contaminated with toxic
flame retardants and heavy metals. None of the products contain more than 30% post-consumer plastic content,
and the PVC and polystyrene products contain no post-consumer recycled plastic content. Competitive products
made from less harmful plastics and higher recycled content are readily available on the market. PVC-based and
polystyrene-based products made of predominantly virgin resin are completely unsustainable products and can
be easily avoided. Nonstructural products made with fiberglass also earn this designation because of the health
impacts associated with fiberglass.
Ratings
Figure 1 lists 30 plastic lumber companies and 38 of their products. Also included are data on these products’
recycled content and main material feedstocks (recycled or not). Appendix 1 lists those companies that did
not provide information upon request. Avoid products from these companies until they inform consumers of
product composition.
Methodology
We identified 67 plastic lumber manufacturers by searching the Internet, especially recycling market and
recycled-content databases,4 and by using our existing knowledge of some companies. In February 2005, all 67
companies were invited to participate in our online survey soliciting data on the companies and their products.
Fifteen companies responded to our survey. We rate these and 15 other companies for which we were able to
obtain data, including the more widely known brands such as Trex and ChoiceDek. [Additional or corrected
information provided to us will be periodically added to the online version of this report. We invite submissions
of company and product data for our database. Contact [email protected].]
A Note on Additives
Plastic lumber contains various additives such as color pigments, UV stabilizers, and sometimes flame retardants.
Analysis of these compounds was beyond the scope of this report.
Rating Disclaimer
Data on material feedstocks and recycled content were provided directly by companies through the survey, by
follow-up calls and emails to manufacturers, and from their Web sites. Material assessments are made solely
based on data provided by companies. Neither the Healthy Building Network nor the Institute for Local SelfReliance has directly tested any of these products for material content, nor have we independently verified any
manufacturers’ claims. No recommendation on performance of these products is made or implied.
7
Figure 1: Plastic Lumber Product Ratings
Brand (Company)
Composition
Recycled Content (%)
Plastics / Other
Postconsumer
Total
Notes
Most Environmentally Preferable
BJM Industries
HDPE, LDPE
100
100
A
Orcaboard (Durable Plastic Design)
HDPE
100
100
A
PlasTEAK (PlasTEAK)
HDPE
100
100
A
HDPE, LDPE
100
100
A
HDPE lumber (U.S. Plastic Lumber)
HDPE
90
90
A
Leisure Deck (The Plastic Lumber Company)
HDPE
80 to 95
100
A
Everlast (Everlast) Plastic Lumber
HDPE
80
100
A
Eco-Tech (Eco-Tech)
HDPE
75 to 100
95 to 100
A
HDPE, LDPE
75 to 95
85 to 95
A
Enviro-Curb (Enviro-Curb Manufacturing)
HDPE
75
100
A
MAXITUF (Resco Plastics)
HDPE
60
100
A
Perma-Deck Advantage+ (Cascades)
HDPE
50
100
A
Eco-Tuff (Eco-Tech)
HDPE
50
90
A
BreezeWood (Aeolian Enterprises)
HDPE
50
50
A
HDPE, LDPE / wood
100
100
B
HDPE / wood
50
100
B
HDPE, LDPE, PP / R
75
100
C
Select (Bedford Technology)
Ameriwood (American Plastic Lumber)
Environmentally Preferable
Evergrain (Epoch Composite Products)
Perma-Deck Elegance (Cascades)
Northern Plastic Lumber
Less Environmentally Preferable
Bear Board (Engineered Plastic Systems)
HDPE
10
98
D
Evolve, Perma-Poly (Renew Plastics Division)
HDPE
NA
90
D
Four Seasons (Delmarva Industries)
HDPE
0
100
D
WindRiver Fence (Aeolian Enterprises)
HDPE
0
0 to 30
D
HDPE, LDPE / wood
30
100
E
PP / wood
1 to 20
70
E
Trex Origins (Trex)
HDPE, LDPE / wood
NA
100
F
fiberon (Fiber Composites)
HDPE, LDPE / wood
NA
50 to 100
F
Latitudes Decking (Universal Forest Products)
HDPE / wood
NA
75 to 88
F
Veranda (Universal Forest Products)
HDPE / wood
NA
75 to 88
F
Monarch (Green Tree Composites)
HDPE / wood
0
75 to 80
F
WeatherBest Select (Louisiana-Pacific)
HDPE / wood
0
60 to 95
F
HDPE, PS
50
100
G
HDPE, LDPE / FG
75 to 95
85 to 95
H
HDPE / FG
65
65
H
HDPE, LDPE / FG
50
95
H
HDPE, PS
30
100
H
PVC / wood
0
45 to 50
I
PVC
NA
NA
I
PS
0
0
J
Many types
30
100
K
ChoiceDek (A.E.R.T., Inc.)
CorrectDeck (Correct Building Products)
Polywood nonstructural (Polywood)
Not Environmentally Preferable Except for Structural Applications
Ameriwood-Plus (American Plastic Lumber)
Trimax (U.S. Plastic Lumber)
FiberForce (Bedford Technology)
Polywood (Polywood)
Not Environmentally Preferable – Avoid
Boardwalk (CertainTeed)
Synboard (Synboard America)
eon (CPI Plastic Group)
XPotential (Xpotential Products)
FG = fiberglass
HDPE = high-density polyethylene
LDPE = low-density polyethylene
PP = polypropylene
PS = polystyrene
PVC = polyvinyl chloride
R = rubber
8
Notes to Figure 1
All brands listed have solid, rectangular profiles except eon.
Total recycled content may include scrap generated from manufacturing. For wood-plastic composites, the total
recycled content includes wood and plastic. These composites are typically 50 to 75 percent wood.
Avoid products from companies that did not respond to information requests. See Appendix of report for a list of
these companies.
A
High post-consumer recycled content, high potential recyclability, AND made from resins associated with
fewer environmental health hazards throughout their lifecycle.
B
Good recycled content but end-of-life recyclability hampered by wood-plastic mixture.
C
High recycled content but made with a mixture of recycled resins which could limit applications as well as
end-of-life recyclability.
D
Low or unknown post-consumer recycled content; similar products with higher post-consumer recycled
content available.
E
Some post-consumer recycled content but end-of-life recyclability still hampered by wood-plastic mixture.
F
Zero or unknown post-consumer recycled content AND combines wood with plastic hampering end-oflife recyclability.
G
Made with recycled pre-consumer polystyrene. Virgin polystyrene is a material associated with a
hazardous production process.
H
Made with polystyrene or fiberglass, materials associated with greater health hazards during their
lifecycle. These products have added strength for demanding structural applications and their use may
be justified for these situations; otherwise avoid.
I
Made with virgin PVC, a material associated with greater environmental health hazards throughout its
lifecycle and that has few recycling options. (Synboard is trim lumber, not decking.)
J
Made with virgin polystyrene, a material made with known and suspected human carcinogenic materials.
K
Contains auto-shredder fluff, which can contain brominated flame retardants and heavy metals.
Disclaimer: Neither the Healthy Building Network nor the Institute for Local Self-Reliance has tested or assessed
any of these products for material content or performance. In addition, we could not fully assess the nature of
additives and did not rate these products based on toxicity of additives such as color pigments.
Source: Healthy Building Network (HBN), 2005. Data for 15 companies was collected via HBN’s February 2005
Web-based survey. For the other 15 companies, data is based on visiting the manufacturer’s Web site and/or by
contacting the company.
9
Rating Criteria and Findings
I. Materials Used
Most plastic lumber products on the market are made from high- and low-density polyethylenes (HDPE and
LDPE). Some manufacturers are also using polystyrene (PS) and polyvinyl chloride (PVC). Some combine
polystyrene or fiberglass with HDPE. Still others rely on a commingled mix of different types of plastic resins
(largely collected from municipal recycling programs).
Presently all the plastics used in plastic lumber are derived from petroleum and natural gas. As such they share
the significant environmental health burdens associated with fossil fuel extraction, refining, and use. They
vary significantly, however, in their environmental and public health implications because of differences in the
chemicals and additives used to achieve the desired properties of the plastic.
In this report, the plastic resins used in plastic lumber are
The toxic hazards of the PVC evaluated and compared for chemical hazards applying a
methodology developed for the City of San Francisco. This
lifecycle from its manufacture, hazard assessment method emphasizes pollution prevention
use, and disposal lead many at the source “by avoiding materials and processes that
use or generate priority hazardous chemicals …that have
to consider it the worst plastic been targeted for reduction or elimination on a select set
from an environmental health of U.S. and international governmental lists.”5 By using
methodology, we link the significance which we place
perspective. this
on the environmental and public health impacts of these
materials to established public policy goals. When applied
against these criteria, some plastic resins are clearly better than others from an environmental and public
health perspective. Polyethylene has fewer chemical hazards and associated impacts than PVC or PS. A similar
conclusion has been reached by other independent authorities including Environmental Building News,6 The
GrassRoots Recycling Network,7 and Greenpeace.8
Figure 2 lists the various plastic resins used to make plastic lumber, and identifies associated health issues and
recyclability potential. In addition, fiberglass is a major component of some plastic lumber, and its human health
impacts also deserve consideration.
Polyethylene (HDPE and LDPE)
High-density polyethylene plastic (HDPE), frequently used to make milk and water jugs and shampoo containers,
is one of the most highly recycled plastics. In 2001, the recycling level for high-density polyethylene (HDPE)
milk and water bottles was 28.4%.9 An average 300-pound picnic table made from recycled HDPE utilizes
between 1,890 and 2,700 milk jugs.10 Low-density polyethylene (LDPE) is used to package cream cheese, butter,
spreads, and other dairy products. In addition, many plastic bags are made from LDPE.
Like all fossil-fuel-based plastics, polyethylene manufacturing is an energy-intensive process that utilizes
numerous toxic and hazardous materials. Emissions of polyethylene manufacturing facilities include a wide
range of persistent, bioaccumulative, and toxic outputs. However, both HDPE and LDPE lack additional toxic
inputs associated with the two other plastics used in plastic lumber, polystyrene, and PVC. This in turn results
in fewer toxic hazards throughout the full production cycle, as well as during routine use and at the end of the
product’s service life.11 Fewer additives and a more uniform composition also help account for the relatively high
recycling rate of HDPE. These properties also suggest that recycled polyethylene products intrinsically have high
recycling potential.
10
Figure 2: Plastics Used in Plastic Lumber
P
Other Common Applications
Health Issues
Recyclability
High-Density
Polyethylene (HDPE)
milk and water jugs, detergent
containers, trash bags
HDPE does not require
toxic plasticizers such
as phthalates. Some
applications use flame
retardant additives, which
if brominated are toxic.
High potential for
mechanical recycling.
HDPE bottles are
collected in most
curbside recycling
programs. In 2001,
28% of HDPE milk
and water bottles
were recycled.
Low-Density
Polyethylene (LDPE)
dry-cleaning, trash, produce,
and bread bags; shrink wrap;
containers for dairy products
LDPE does not require
toxic plasticizers such
as phthalates. Some
applications use flame
retardant additives, which
if brominated are toxic.
Technically can be
recycled; actual
recycling levels
are under 3%.
Infrastructure for
collection of LDPE
wrap and bags is
not well developed.
Polystyrene (PS)
foam insulation, packaging
peanuts, plastic utensils,
meat trays, egg cartons,
take-out containers, singleuse disposable cups
PS production uses
benzene (a known human
carcinogen), and styrene and
1,3-butadiene (suspected
human carcinogenic
substances). Styrene is a
neurotoxin and is known to
be toxic to the reproductive
system. PS releases toxic
chemicals when burned.
Recycling level
is negligible,
less than 1%.
Polyvinyl Chloride
(PVC or vinyl)
Most PVC is used in building
materials such as pipes,
siding, membrane roofing,
flooring, and window
frames as well as in other
consumer products such
as shower curtains, beach
balls, and credit cards
PVC is made from the vinyl
chloride monomer, a known
human carcinogen. PVC has
a high chlorine and additive
content. Toxic additives such
as phthalate softeners are
not bound to the plastic and
leach out. PVC releases
dioxin and other persistent
organic pollutants during its
manufacture and disposal.
Recycling level is
negligible. At trace
quantities, PVC can
interfere with the
recycling of other
resins such as HDPE
and polyethylene
terephthalate (PET)
used in soda and
water bottles.
R
E
F
E
R
5
5
5
5
5
5
5
5
A
V
O
I
D
Source: Healthy Building Network, 2005.
11
Polyvinyl Chloride (PVC)
PVC plastic, commonly known as vinyl, is
unique in that its composition is at least 50%
chlorine content by weight. PVC uses about
a third of the world’s chlorine production.
The toxic hazards of the PVC lifecycle from
its manufacture, use, and disposal lead many
to consider it the worst plastic from an
environmental health perspective. Production
and disposal of PVC releases – into the air,
water and land – persistent pollutants that
present both acute and chronic health hazards.
They are known to cause cancer, disrupt the
endocrine system, impair reproduction, cause
birth defects, impair child development,
damage the brain, disrupt the immune system,
and cause endometriosis and neurological
damage. Many of these pollutants, especially
dioxins, are dispersed throughout the world
and exist in the bodies of most Americans at
detectable levels.12 13
The Chlorine Factor: The Problem with PVC
PVC is made from the monomer vinyl chloride, classified by
the U.S. Environmental Protection Agency as a known human
carcinogen. Vinyl chloride is made from substantial amounts of
chlorine. It is the chlorine in PVC that contributes to the formation
of dioxin, another human carcinogen, during production, and
when it burns in fires or waste incinerators. Because of its high
chlorine content and large production volumes, PVC is likely
the largest material source of dioxin to the environment.
Dioxin is a persistent bioaccumulative toxic chemical (PBT). It does
not degrade rapidly, accumulating in fatty tissue and concentrating
as it goes up the food chain. For example, dioxins from Louisiana
manufacturing plants migrate on the wind and concentrate in Great
Lakes fish. Dioxins are even found in hazardous concentrations
in the Arctic Circle in the tissues of whales and polar bears and
in Inuit mothers’ breast milk. The dioxin exposure of the average
American already poses a calculated risk of cancer of greater
than 1 in 1,000. Even worse, dioxins concentrate in breast
milk to the point that human infants now receive high doses,
orders of magnitude greater than those of the average adult.
Dioxins are among a class of synthetic chemicals known as
endocrine disruptors, chemicals that mimic the role of hormones
in human biology and that are believed to interfere with each
stage of human development – damaging the male sperm,
the female egg prior to fertilization, and the fetus in utero.
Finally, PVC is useless without the addition
of a plethora of toxic chemical stabilizers
In the US, PVC is manufactured predominantly near low-income
– such as lead, cadmium and organotins – and
communities in Texas and Louisiana. The toxic impact of pollution
phthalate plasticizers. These are required to
from these factories on these communities has made them a
focus in the environmental justice movement. Chlorine is also a
keep PVC from breaking down and to make it
highly toxic chemical and makes the PVC manufacturing plants
flexible or rigid as needed. They are, however,
and the trains that supply them highly vulnerable. A simple
not permanently bound to the PVC but rather
terrorist attack could release a toxic cloud or clouds that would
slowly released from the PVC. The resulting
spread for miles, potentially endangering millions of lives.
pollution presents risks that include asthma,
Source: Thornton, Joe. Pandora’s Poison: Chlorine, Health and a New Environmental
lead poisoning, birth defects, and cancer.
Strategy (March 2000, MIT Press); and Thornton, Joe. Environmental Impacts of
Polyvinyl Chloride Building Materials. Washington: Healthy Building Network, 2002.
The multitude of additives required to make
PVC useful make large scale post-consumer
recycling nearly impossible for most products
and interfere with the recycling of other plastics. The Association of Post Consumer Plastics Recyclers declared
PVC a contaminant in 1998.14 PVC also poses a great risk in building fires. Long before it ignites, PVC releases
deadly gases such as hydrogen chloride, which turns to hydrochloric acid in contact with moisture, such as in the
lungs when inhaled. As PVC burns, whether intentionally in waste incinerators or burn barrels, or accidentally in
building or landfill fires, it releases yet more toxic dioxins.15
Polystyrene (PS)
The process of manufacturing polystyrene includes benzene, ethyl benzene, and the monomer styrene. Benzene
is a known carcinogen. Ethyl benzene is a possible carcinogen. Styrene is a suspected human carcinogen and a
known neurotoxin which can attack the central and peripheral nervous systems.16 Styrene also adversely affects
the digestive, respiratory, and endocrine systems.17 Styrene is considered a hormone-disrupting chemical.18
Burning polystyrene poses further health impacts. One study indicates that when burned at temperatures of
800-900 degrees Celsius (the typical range of a modern incinerator), the products of polystyrene combustion
consisted of “a complex mixture of polycyclic aromatic hydrocarbons (PAHs) from alkyl benzenes to
12
benzo[ghi]perylene. Over 90 different
compounds were identified in combustion
effluents from polystyrene.”19 In addition,
like PVC, polystyrene is recycled at negligible
levels due in part to technical difficulty and
in part to difficulty and impracticality of
establishing an infrastructure for collecting
polystyrene discards.
Fiberglass
Some companies add fiberglass to reinforce
plastic lumber and enable it to bear loads
comparable to wood lumber. Fiberglass
is a “mechanical irritant” and any
surface fiberglass should be removed for
applications where human or animal skin
will come into contact with the material.20
More importantly fiberglass has been linked
to pulmonary disease, affecting the lungs in
a manner similar to asbestos, though not as
virulent. In 1987, The International Agency
for Research on Cancer listed fiberglass as
a “probable [human] carcinogen.” By 1994,
the U.S. National Toxicology Program in
its Seventh Annual Report on Carcinogens
noted that fiberglass is “reasonably
anticipated to be a carcinogen.”21 Workers
machining fiberglass-reinforced plastic
lumber are advised to wear a properly fitting
NIOSH22 approved dust mask for respiratory
protection and to wear protective gloves
when handling it.23
Although manufacturers using fiberglass
claim that respirable glass fibers are present
at de minimus levels during manufacturing
and use,24 we know of no independent
studies that support this claim with data
gathered during the manufacturing process,
or during the sawing and grinding typically
associated with product usage and recycling
operations respectively.
Findings
Polyethylene plastic lumber products are
clearly preferable to those manufactured
with PVC, polystyrene, or fiberglass.
While still burdened with the significant
environmental problems associated with all
Aren’t all plastics bad?
A 1996 Report of the Berkeley Plastics Task Force found that
a link exists between the promotion of plastics recycling and
an increase in production of virgin resin.1 The most recycled
plastics are HDPE, LDPE, and polyethylene terephthalate (PET,
commonly used for soda bottles). Their combined recycling
rate is 8%.2 The recycling level for all other types of plastics
combined is less than 3%. Plastics recycling can also be used
to justify the production of disposable and single-use packaging
and thus thwart any efforts to switch to biodegradable or reusable
materials.3 Plastic is the fastest growing part of the waste stream
and by far the most expensive for cities to manage. Plastic waste
also threatens the very life of the ocean. Recent research, for
example, reveals that the ocean surface has six times more
mass of plastic pieces than zooplankton, the source of life.4
The manufacture of virgin plastics from fossil fuels is causing serious
damage to our environment. Refining petroleum and making virgin
plastics consumes energy and releases pollution, some of which
is highly toxic. (Plastics production accounts for 4 percent of all
U.S. energy consumption.5) All fossil-fuel-based plastics contain or
release some carcinogens at some point in their lifecycle. Some
– like PVC and polystyrene – rely upon additional toxic chemicals,
which make their environmental health impact even greater.
On the other hand, plastic lumber reduces demand for other
materials having serious environmental impacts. Many people
do not realize that “pressure-treated” wood widely used for
decks and fences is infused with chemicals. Even though the
worst of these (arsenic and chromium) have been drastically
curtailed, they have not been totally eliminated. All pressuretreated wood still contains copper, which alone renders the
wood unacceptable for chipping and mulching. The wood itself,
as well as naturally rot-resistant species like redwood, usually
comes from unsustainable timber operations. Plastic lumber
also competes with other materials such as concrete, steel
and aluminum, which have high environmental impacts.
Clearly some plastics, such as PVC and polystyrene, are not only
bad, but also easily replaced by other materials, including other
plastics. These plastics must be phased out of production and
use. Phasing out the worst plastics, halting the indiscriminate
use of plastics – especially in non-durable goods – increasing
the societal commitment to mandatory plastics recycling, and
increasing investment in bio-based plastics hold out the prospect
that some plastics may have a role in a sustainable economy. In
that context, recycled plastic could play a role in reducing the
demand for virgin plastic resin and the volume of plastic waste.
1 Report of the Berkeley Plastics Task Force, April 8, 1996,
available online at http://www.ecologycenter.org/ptf.
2 U.S. EPA Office of Solid Waste and Emergency Response,
Municipal Solid Waste in The United States: 2001 Facts and Figures,
EPA530-R-03-011 (Washington, DC: October 2003).
3 Woolley, Tom and Sam Kimmins. Green Building Handbook: A Guide to Building
Products and Their Impact on the Environment, Vol. II. London: E & FN Spon, 2000.
4 “Plastic Debris: Rivers to Sea,” Algalita Marine Research
Foundation Web site at http://www.plasticdebris.org.
5 “Plastics,” Municipal Solid Waste Web site of the U.S. Environmental Protection
Agency, http://www.epa.gov/epaoswer/non-hw/muncpl/plastic.htm.
13
fossil-fuel-based plastics, polyethylene lacks many of the unique environmental and health impacts associated
with PVC, polystyrene, and fiberglass. For these reasons, we rate polyethylene feedstocks as most environmentally
preferable, downgrade any product whose composition combines other materials that “contaminate” the
polyethylene, and recommend avoiding the use of PVC, polystyrene, and fiberglass – especially products made
from virgin PVC or polystyrene such as Synboard, CertainTeed’s Boardwalk and CPI’s eon.
II. Recycled Content
Plastic lumber products range from 100% recycled content to those made entirely from newly manufactured or
“virgin” PVC.
Our ratings value recycled content and recyclability of the product strongly not only because of the reduction
in raw materials consumption and solid waste, but because of the reduction in the environmental and health
impacts of production and disposal. Recycling can save energy, reduce air and water pollutants, and cut
greenhouse gases that contribute to global warming.25
Furthermore, buying recycled products supports local
recycling initiatives by increasing demand for material
collected. This in turn creates jobs and can help strengthen
local economies, especially if materials are made into
finished products within local economies. This is often
the case with many plastic lumber companies who obtain
recycled feedstocks from local or regional sources.
Plastic lumber products range
from 100% recycled content to
those made entirely from newly
manufactured or “virgin” PVC.
Recycled plastic lumber can potentially utilize a high proportion of polyethylene plastics in the waste stream. In
the late 1990s, total recycled plastic lumber production was about 16 million board feet (about 40 million pounds
of discarded plastics). By 2001, total production had climbed to more than 120 million board feet (about 300
million pounds of discarded plastics). The current annual growth rate for this industry is about 40 percent.
However, the consumption rate of plastic lumber is still a fraction of what it is for softwood lumber (about 34
billion board feet per year).26
Post-consumer vs. Post-industrial Recycled Plastic Content
Recycling experts generally value post-consumer recycled materials higher than post-industrial. Post-consumer27
recycled materials come from products that have already been used and discarded by a business or consumer, as
opposed to post-industrial (also called pre-consumer) recycled materials that are from manufacturing waste. It is
important to distinguish the two.
Obviously recycling industrial plastic scraps is preferable to disposing them, but for most manufacturing
operations this has long been a standard business practice. Therefore, the use of post-industrial, pre-consumer
recycled materials in plastic lumber does not represent an improvement over current practice. Because the use of
pre-consumer or post-industrial content does not meaningfully reduce the overall consumption of raw materials
and disposal of products, we do not reward the use of post-industrial recycled content plastic.
Findings
Recycled content varies among plastic lumber products that claim post-consumer content. More than two-thirds
of the products we review contain post-consumer plastic content. We give the most credit to products that have
a minimum of 50% post-consumer recycled content and a composition with a high potential for end-of-life
recyclability. We give lower ratings to products that have less than 50% minimum post-consumer content, or
whose mixtures limit the products’ own potential recyclability. We also rank lower products that contain plastics
recovered from shredded automobiles, known as auto-shredder fluff, because these are known to contain heavy
metals and other toxic chemicals.
14
III. End-of-Life Recyclability: A Facet of Sustainable Design
In order to make a significant long-term impact on reducing resource use and disposal, it is not only important
that plastic lumber include recycled content, but also that the lumber product itself be recyclable at the end
of its life. Otherwise the material will still eventually end up in an incinerator or landfill. Plastics use overall is
increasing, while plastics recycling fails to keep pace with that growth.28 Plastic lumber could help close that gap
– or it could just provide greenwash incentive for more plastic manufacturing and use.
Plastic lumber is currently largely made from first-use applications that are not environmentally sound, like
packaging made from virgin plastic.29 Unless plastic lumber is itself truly, efficiently recyclable and thus can
become part of a closed-loop system of plastic products being indefinitely recycled, a growing plastic lumber
market could actually increase plastics production and waste volumes.
Some manufacturers claim that their plastic lumber products (including wood-plastic composite lumber) are
recyclable.30 These claims cannot be easily tested at this time. Although most manufacturers claim that there
are few technical barriers to recycling their product, the same could be said for most plastics in use today, or
bottles or cans or paper, most of which goes unrecycled in the United States for the lack of infrastructure and
the public policy to support it. Even if original manufacturers are able to recycle their products once they
come out of service, experience shows that in the absence of legislation or a well-developed infrastructure,
this is unlikely to happen.
While plastic lumber has been in use for the
last 15 years, it is a durable product and little
of it has yet to come out of service. 31
Therefore, there is not enough experience
with plastic lumber to determine whether
or not it will be feasible to recycle after its
service life. A number of plastic lumber
manufacturers take back scraps from
construction or installation and recycle this
material back into their product lines. Some
companies producing all-HDPE plastic
lumber are even selling scraps to third-party
recyclers.32 However, this is far different than
recycling the product once it has reached the
end of its service life.
Municipal recycling programs generally
do not accept and recycle plastic lumber.
However, private sector recycling at
construction demolition and building sites
is a growing trend. Successful construction
material recovery efforts involve segregating
materials by type such as wood, metal,
bricks, and gypsum board. Few if any
building products are sent back to original
manufacturers. Thus it is likely that if plastic
lumber is to be recycled efficiently after its
service life, it will have to be marketable to
multiple end users. Because of this, product
Will recycled-content
products perform as well as their
virgin-materials-based counterparts?
The U.S. Environmental Protection Agency (EPA) issues
recommended guidelines for buying a variety of recycledcontent products, including plastic lumber products such as
landscaping timber, park benches and tables, and fencing. These
Comprehensive Procurement Guidelines, which are updated
every two years, recommend post-consumer recycled content
– as well as total recovered content – for specific products. U.S.
EPA research indicates that items designated in its guidelines can
perform as well as products made with virgin materials. Many
federal, state, and local agencies have purchased recycledcontent plastic lumber for a wide range of end uses and have
been pleased with product performance and cost effectiveness.
The American Society for Testing and Materials (ASTM) has
coordinated the development of performance-based industry
standards for plastic lumber products. It has developed nine
standard specifications for plastic lumber and more are on the
way. These standards include test methods, specifications,
recommended practices, and definitions for dimensional profiles
made from recycled plastics. ASTM’s latest standard on polyolefinbased plastic lumber decking boards, for instance, addresses the
proper use of recycled plastic lumber and resolves issues such
as dimensional tolerances, creep, allowable material properties
for structural design, outdoor weathering, and UV exposure.
For more information on EPA’s Comprehensive
Procurement Guidelines, visit http://www.epa.gov/cpg
For more information on ASTM’s plastic lumber
standards, visit http://www.astm.org
15
composition assumes greater importance. One major factor that will likely impact the recovery of plastic
lumber is its composition.
Single Resins
More than a dozen companies offer lumber made from a single resin, polyethylene, most commonly HDPE, one
of the most recyclable and recycled plastics. (Some products also use LDPE, a low-density version of the same
resin.) Plastic lumber made from a single recyclable resin has more recycling possibilities than lumber made
from mixtures.
To be economically feasible, plastics recycling must have
sufficient volumes to support the necessary infrastructure
to handle the materials separately from solid waste,
and provide a reliable resource stream to end users.
Although setting up dedicated recovery systems for
each plastic lumber blend is theoretically possible, there
is no evidence to suggest that such a system would be
economically feasible.
A growing plastic lumber market
could actually increase plastics
production and waste volumes.
The most successful plastics recycling ventures – municipal beverage container recycling programs – teach that
avoiding contamination of desirable commodities such as polyethylene increases their value.33 Indeed, because
HDPE has one of the highest plastics recycling levels, there is ample reason to believe that HDPE lumber is the
most likely plastic lumber product to be routinely recycled by far. Some companies making all-HDPE lumber
currently sell returned cut-offs to third party recyclers, providing further confirmation that “pure” resin lumber
will have more recycling options than composites.34
Synthetic Composites
Some plastic lumber manufacturers combine different plastics or add fiberglass to their product. With the
exception of high load-bearing or demanding structural applications (see below), there appears to be no
clear environmental advantage and numerous environmental disadvantages to these mixtures, because of the
chemical hazards and associated impacts of the additional materials such as PVC, polystyrene, fiberglass, and
the mixed plastics in automobile fluff. Another disadvantage is the lack of a viable recycling option after the
service life of the product.
Composite products are usually more difficult to recycle than single-resin products, have fewer end markets,
and are therefore inherently less valuable to secondary markets than a “pure” product. There is no evidence
to suggest that there will be an end market for synthetic composite lumber products, other than the original
manufacturer. It is not likely to be economically feasible to systematically return all plastic lumber to the
manufacturer at the end of its service life.
Wood-Plastic Composites
Many lumber manufacturers blend wood fiber with plastics. While this may reduce the use of non-renewable
plastics, there are several environmental disadvantages to this formula. As with other composites, the record
of plastics recycling to date shows that “contaminating” the polyethylene with another material is likely to limit
long-term recycling options.35 The decision to inextricably combine a biodegradable material with a synthetic
material also appears to violate a fundamental principle of sustainable design, which is to segregate synthetic
from biological materials.36
Furthermore, it is unknown whether or not a plastic lumber product containing biodegradable materials can be
technically recycled after 10 or more years of exposure to the elements.
16
Findings
Plastic lumber has not been on the market long enough to evaluate recycling rates for products at the end of their
service life. The record of plastics recycling to date suggests that polyethylene is one of only two plastic resins
to be recycled systematically. (The other is polyethylene terephthalate – PET, commonly used for soda bottles
– which is not a main feedstock material for plastic lumber.) For all low load-bearing plastic lumber applications,
there are all-polyethylene lumber products with high recycled content. Therefore we give a lower rating to
products that combine other materials with HDPE or LDPE.
IV. Structural Lumber: The Exception to the Rule
In general we downgrade plastic lumber products that combine fiberglass or polystyrene feedstocks with
polyethylene. At the present time, however, all plastic lumber products suitable for demanding structural or high
load-bearing applications rely upon one of these combinations for added strength. These applications include
bridge supports and railroad ties. Because structural plastic lumber products compete directly with wood that
is treated with toxins such as arsenic, copper, chromium and creosote, which also present environmental and
health hazards throughout their lifecycle, composite plastic lumber has advantages in these applications that may
outweigh the disadvantages of these composites, such as leaching while in service.
17
Recommendations
The Healthy Building Network endorses the following guidelines for plastic lumber purchases. These guidelines
are based on environmental, public health, and recycling considerations.
Ø Favor products:
o
with high recycled content, specifically high post-consumer recycled content.
o
made from high-density and low-density polyethylene (HDPE and LDPE), recyclable resins
associated with fewer chemical hazards and impacts than other petroleum-based polymers.
o
by producers sourcing resins from local municipal recycling programs, therefore cutting
transportation costs and supporting the local economy.
Ø Limit use of:
o
wood-plastic composites because of concerns about mixing biological and synthetic materials,
including limited end-of-life recyclability.
o
fiberglass-reinforced or polystyrene-blended “structural” plastic lumber to demanding structural
applications such as railroad ties and bridge supports, as a less toxic alternative to chemically treated
wood.
o
products with multiple commingled recycled consumer plastics as they will have more
contaminants and inconsistent properties. They also support token markets for plastics that
otherwise are largely unrecyclable, and many of which are highly toxic. This perpetuates the use of
plastics that should be phased out.
Ø Avoid products made with:
o
PVC and polystyrene because these are associated with more chemical hazards and impacts
throughout their lifecycle than other plastics.
o
fiberglass for nonstructural applications that do not require reinforced plastic lumber (such as
decking boards, benches, and tables).
o
predominantly nonrecycled plastics. Alternatives with high recycled content are readily available.
18
How to Choose
Check Healthy Building Network’s ratings: HBN’s ratings will help identify which brands to avoid and which ones
are more environmentally preferable.
Know your application: Different products have different performance qualities. Take the time to understand the
properties of the particular plastic lumber you buy, particularly whether it will be used in demanding structural or
high-load-bearing applications. The most environmentally preferable HDPE-only plastic lumber can be used for
many plastic lumber applications: benches, tables, decking, playground equipment, and more. HDPE-only plastic
lumber does not have the same load-bearing capacity as wood, so it won’t work for bridge supports and other higherload-bearing applications. No high-load-bearing plastic lumber products – such as fiberglass-reinforced plastic
or polystyrene-polyethylene blends – earn our most environmentally preferable rating. For certain applications,
however, they may actually be preferable to the products they replace. A good example may be railroad ties, which
have traditionally been made from creosote-soaked wood, or chemically treated wooden bridge supports. When
choosing a more engineered plastic for demanding structural situations, at minimum look for high post-consumer
content.
Beware of nontoxic claims and greenwashing: Despite claims of being “green,” not all plastic lumber products are
created equal. If the product is made from PVC or polystyrene, be assured it is not environmentally preferable.
Lumber made from high-density and low-density polyethylene (HDPE and LDPE) and 100% post-consumer
recycled content is the most environmentally preferable currently available on the market. Most manufacturers add
additives such as color pigments and UV stabilizers to prevent polymer breakdown in the sun. Some companies
acknowledge the “possible risk of exposure to hazardous ingredients” but tend to emphasize that the risk “is reduced
to encapsulation in plastic.”37 These claims have not been verified.
Talk to suppliers: Insist that suppliers offer the most environmentally preferable products. (Most lumber yards offer
a limited selection and this tends to feature the wood-plastic composites. Lowe’s offers ChoiceDek, Home Depot
offers Veranda, and many offer Trex, all of which fall in our “Less Environmentally Preferable” category.) Also request
that suppliers recycle installation scraps and cut-offs and let them know that recycling is important to you.
Consider where you live: Many of the companies making recycled-content lumber products are small-scale
enterprises that obtain their recycled feedstocks from local and regional municipal recycling programs and largely
market their lumber within the same region. If you live near one of these enterprises, your purchase can help divert
plastic waste from disposal and contribute to local economic development and job creation. More than 1,800 U.S.
businesses handle or reclaim post-consumer plastics.38 In contrast, only a handful of corporations make virgin resins.
If you live in an area where sustainably harvested lumber products are locally grown, produced, and sold, these may
be your greenest choice. Look for lumber certified by the Forest Stewardship Council (FSC), which ensures that the
wood was grown and harvested in a manner that balances economic, environmental, and social justice concerns. See
http://www.fscus.org for more information.
Dollars & Sense: Plastic lumber is generally more expensive than wood, but it may be more durable and does not
need sealants, preservatives or paint, so the savings in maintenance expenses can outweigh the initial costs. When
materials and installation, maintenance, replacement, and disposal costs are included in a cost analysis, recycled
plastic lumber can cost less than wood.39
High-volume purchasers: Government agencies and other high-volume purchasers can specify environmentally
preferable products in their purchasing policies. In addition, procurement contracts with plastic lumber vendors
can encourage collection and recycling of plastic lumber products once they have served their intended use. (The
Commonwealth of Massachusetts, Operational Services Division, specifies in its procurement language for recycled
plastic equipment that “it is desirable that bidders offer recycling options” for such products.40)
19
Conclusions
More than one-third of the products reviewed in this report are identified as “Most Environmentally Preferable.”
These products are made from polyethylene, a highly recyclable plastic, and thus have a realistic chance of being
recycled after their service life. All have at least 50% post-consumer content, and a number of these are made
from 100% post-consumer recycled content. This suggests that the most environmentally preferable products can
also become the industry standard in plastic lumber products.
Manufacturers of composite products (those containing mixtures of plastics, fiberglass, or wood-plastic
mixtures) sometimes claim performance advantages, such as greater strength and less heat retention and
slipperiness. Manufacturers of HDPE-only products counter that they are able to engineer comparable features
and performance into noncomposite products for most applications. According to the Consumer Reports
Magazine review of plastic lumber (which did not distinguish among the plastics used), “In most instances, one
type will serve as well as another.”41 We identified only one exception to the general preference for 100% postconsumer HDPE products – demanding structural applications. Presently it appears that the only plastic lumber
products suitable for demanding structural applications obtain their additional strength from polystyrene or
fiberglass that is added to make a composite product. Consequently, we conclude that is the only exception to the
general rule to buy all-polyethylene products.
In summary, the plastic lumber market manifests high potential to create a closed-loop system for using large
volumes of post-consumer HDPE plastic over the long term. This is an excellent opportunity for retailers and
consumers to steer this emerging market toward its greatest sustainability potential by selecting these products.
Manufacturers should concentrate research and development programs towards optimizing these products, and
especially developing the infrastructure necessary to ensure recycling of their products after their service life.
20
Resources
RecyclingMarkets.Net
Recycling Markets
P.O. Box 577
Ogdensburg, NY 13669
[email protected]
http://www.recyclingmarkets.net
A searchable database of more than 17,000 U.S. and Canadian companies involved in the recycling process. It
includes manufacturers and distributors of plastic lumber and decking and of products constructed from these
materials. Companies in the database must meet the Recycled Products Guide (RPG) certification of recycled
content in their products.
Recycled-Content Product Directory
California Integrated Waste Management Board
1001 I Street, Sacramento, CA 95812
http://www.ciwmb.ca.gov/RCP
A searchable database of vendors who sell or distribute products with recycled content. Its database lists postconsumer as well as total recycled content and has links to company Web sites.
Comprehensive Procurement Guidelines (CPG)
1200 Pennsylvania Avenue
Washington, DC 20460
[email protected]
http://www2.ergweb.com/cpg
A searchable database of vendors who sell or distribute CPG-designated products with recycled content. This
powerful tool allows users to search for vendors of a specific CPG product, product category, or type of material.
Building Green, Inc.
122 Birge Street, Suite 30
Brattleboro, VT 05301
[email protected]
http://www.buildinggreen.com
An independent company that provides information for building-industry professionals and policy makers
who want to reduce the environmental impacts and natural-resource demands of buildings. Publisher of
Environmental Building News, The GreenSpec Directory, and Green Building Advisor.
Green Resource Center (GRC)
PO Box 11944
Berkeley, CA 94712
[email protected]
http://www.greenresourcecenter.org
The GRC’s Web site provides an extensive source of information about green building and includes links to many
other organizations and sources. It also has a fact sheet on “Recycled Plastic Lumber.”
21
Appendix 1:
Plastic Lumber Companies That Did Not Respond to
Our Inquiries or Survey
The following companies did not respond to our survey or requests for data on their products. Avoid their
products until they inform consumers about product composition. We will periodically add products and update
content information on our Web listing and the Web version of this report. Please submit company/product
updates to [email protected].
Company
Brand Name
Amazing Recycled Products
Aztec Plastic Lumber
Black Rhino Recycling
Center Industries Ltd.
Cooley Forest Products
Geodeck, cactus pine, Pyro-Guard
Duraplex Inc.
Earth Technology Corporation
Envirosafe Products Corp.
Permawood, Duraplast, Permapost, Permafloor
Fibrex Group Inc.
The FiberX Group envirodesign
Inteq Corporation
J L Sims Company, Inc.
J-Mac Lumber Inc.
MacLumber II
Outwater Plastics Industries Inc.
P&M Plastics Inc.
Altree
Phoenix Recycled Plastics
Foreverdeck, Foreverdock
Plastic Lumber Depot
Plastic Recycling of Iowa Falls
Play Mart, Inc.
RSP
22
Appendix 2:
Contacts for Plastic Lumber Companies
A.E.R.T., Inc. (ChoiceDek)
http://www.aertinc.com
Aeolian Enterprises (BreezeWood)
http://www.aeo1.com
American Plastic Lumber (Ameriwood3)
http://www.american-plasticlumber.com
Bedford Technology (Select)
http://www.plasticboards.com
BJM Industries
http://www.bjmindustries.com
Cascades (Perma-Deck Advantage +)
http://www.cascadesreplast.com/english/fs_replast.html
CertainTeed (Boardwalk)
http://www.certainteed.com/certainteed/index.htm
Correct Building Products (CorrectDeck)
http://www.correctdeck.com
CPI Plastic Group (eon)
http://www.cpiplastics.com
Delmarva Industries (Four Seasons)
http://www.delmarvaindustries.com/index.html
Durable Plastic Design (Orcaboard)
http://www.orcaboard.com
Eco-Tech (Eco-Tech)
[email protected]
Engineered Plastic Systems (Bear Board)
http://www.epsplasticlumber.com
Enviro-Curb Manufacturing (Enviro-Curb)
http://www.envirocurb.com
Epoch Composite Products (Evergrain)
http://www.evergrain.com
Everlast Plastic Lumber (Everlast)
http://www.everlastlumber.com
Fiber Composites (fiberon)
http://www.fiberondecking.com/sitemap.asp
Green Tree Composites (Monarch)
http://www.biewerlumber.com/greentree.htm
Louisiana-Pacific (WeatherBest Select)
http://www.lpcorp.com
Northern Plastic Lumber
http://www.northernplasticlumber.com
PlasTEAK (PlasTEAK)
http://www.plasteak.com
Polywood (Polywood nonstructural)
http://www.polywood.com
Renew Plastics Division (Evolve, Perma-Poly)
http://www.RENEWPlastics.com
Resco Plastics (MAXITUF)
http://www.rescoplastics.com
Synboard America (Synboard4)
http://www.synboard.com
The Plastic Lumber Company
http://www.leisuredeck.com
The Plastic Lumber Company (Leisure Deck)
http://www.leisuredeck.com
Trex (Trex Origins)
http://www.trex.com
U.S. Plastic Lumber (HDPE)
http://www.usplasticlumber.com
Universal Forest Products (Latitudes Decking)
http://www.latitudesdeck.com
XPotential Products (XPotential)5
http://www.xpotentialproducts.com
23
End Notes
Alan E. Robbins, “The Plastic Lumber Industry in Competitive Markets, 2001-2002 State of the Recycled Plastic Lumber
Industry,” presented at The Annual Meeting of the Plastic Lumber Trade Association, March 11, 2002, Pittsburgh,
Pennsylvania. Available online at http://www.plasticlumber.org.
1
See for example the Minnesota Office of Environmental Assistance plastic lumber Web page at http://www.moea.state.mn.us/
lc/purchasing/plasticlumber.cfm; “Why Use Recycled Plastic Lumber?” Publication #431-97-009, California Integrated Waste
Management Board, Sacramento, California, March 1997, available online at http://www.ciwmb.ca.gov/plastic/recycled/
Lumber; and the Markets Initiatives Alternative Suppliers Database at http://www.oldgrowthfree.com/suppliers.php3, which
lists companies offering alternatives to old growth wood-derived products.
2
3
See for instance “Decking: Serious Alternatives,” Consumer Reports (July 2004), pp. 22-25; Jennifer Lucich, “Party on the
Patio, Alternative Materials Help Make the Most of Outdoor Spaces,” E Magazine (May 2005); and Environmental Building
News articles such as “Recycled Plastic Lumber,” (July/August 1993) and its GreenSpec Directory featuring dozens of plastic
lumber products, available at http://www.buildinggreen.com.
See www.recyclingmarkets.net (a searchable database of more than 17,000 U.S. and Canadian companies involved in the
recycling process) and the California Integrated Waste Management Board’s Recycled-Content Product Directory available at
http://www.ciwmb.ca.gov/RCP.
4
Rossi, Harvie and Lent. Plastic Pipe Alternatives Assessment. San Francisco Department of Environment. February 2005.
http://www.healthybuilding.net/pvc/SFE_Plastic_Pipe_Alts_Assess.pdf, p. 2.
5
Williams and Yost, “Plastics in Construction: Performance and Affordability at What Cost?” Environmental Building News
(July/August 2001).
6
Peter Anderson, RecycleWorlds Consulting, Message In A Bottle (GrassRoots Recycling Network, 2004), available online at
http://www.healthybuilding.net/pvc/PVCBottleRecyclingReport.pdf
7
8
“PVC Alternatives Database,” Greenpeace Web site at http://archive.greenpeace.org/toxics/pvcdatabase/bad.html.
U.S. EPA Office of Solid Waste and Emergency Response, Municipal Solid Waste in The United States: 2001 Facts and Figures,
EPA530-R-03-011 (Washington, DC: October 2003).
9
Background Document for the Final Comprehensive Procurement Guideline (CPG) III and Final Recovered Materials Advisory
Notice (RMAN) III, EPA530-R-00-002, U.S. Environmental Protection Agency (Washington, DC: Sept. 1999), p. 80, available
online at http://www.epa.gov/cpg/pdf/backgr1.pdf.
10
For applicable comparative analyses of polyethylene, PVC and styrene bearing plastics see Williams and Yost, “Plastics in
Construction: Performance and Affordability at What Cost?” Environmental Building News (July/August 2001); see also Rossi,
Harvie and Lent. Plastic Pipe Alternatives Assessment. San Francisco Department of Environment. February 2005.
http://www.healthybuilding.net/pvc/SFE_Plastic_Pipe_Alts_Assess.pdf, p. 2.
11
12
Thornton, Joe. Environmental Impacts of Polyvinyl Chloride Building Materials. Washington: Healthy Building Network, 2002.
Woolley, Tom and Sam Kimmins. Green Building Handbook: A Guide to Building Products and Their Impact on the
Environment, Vol. II. London: E & FN Spon, 2000.
13
Peter Anderson, RecycleWorlds Consulting, Message In A Bottle (GrassRoots Recycling Network, 2004), available online at
http://www.healthybuilding.net/pvc/PVCBottleRecyclingReport.pdf
14
Thornton, Joe. Pandora’s Poison: Chlorine, Health and a New Environmental Strategy (March 2000, MIT Press); and
Thornton, Joe. Environmental Impacts of Polyvinyl Chloride Building Materials. Washington: Healthy Building Network, 2002.
15
National Institute of Health, U.S. National Library of Medicine, Specialized Information Services Web site at
http://hazmap.nlm.nih.gov/cgi-bin/hazmap_generic?tbl=TblDiseases&id=326
16
17
Environmental Defense Scorecard: Chemical Profiles. http://www.scorecard.org/chemical-profiles.
18
See for instance, “Fact Sheet on Hormone-Disrupting Chemicals,” available on the Web page of Rachel’s Environment &
Health News at http://www.rachel.org/library/getfile.cfm?ID=6.
24
R.A. Hawley-Fedder, M.L. Parsons, and F.W. Karasek, “Products Obtained During Combustion of Polymers Under
Simulated Incinerator Conditions, II Polystyrene,” Journal of Chromatography, #315, 1984, Elevier Science Publishers B.V.,
Amsterdam, The Netherlands. Summary of results available online at http://www.ejnet.org/plastics/polystyrene/disposal.html.
19
U.S. Plastic Lumber Group’s material safety data sheet for its semi-reinforced plastic lumber, undated. Available online at
http://www.usplasticlumber.com.
20
21
Fiberglass Information Network Web page at http://www.sustainableenterprises.com/fin/index.htm; “A Carcinogen
That’s Everywhere,” Rachel’s Environment & Health News, #444 (May 31, 1995), available online at http://www.rachel.org/
bulletin/bulletin.cfm?Issue_ID=681&bulletin_ID=48; and Peter Montague, Rachel’s Environment & Health News, personal
communication, May 2005.
22
The National Institute for Occupational Safety & Health
U.S. Plastic Lumber Group’s material safety data sheet for its semi-reinforced plastic lumber, undated. Available online at
http://www.usplasticlumber.com.
23
24
Ibid.
25
U.S. EPA, Greenhouse Gas Emissions from Management of Selected Materials in Municipal Solid Waste, EPA530-R-98-013
(Washington, DC: U.S. EPA, September 1998), pp. ES-1, ES-2; and Recycling for the future… Consider the benefits, prepared by
the White House Task Force on Recycling (Washington, DC: Office of the Environmental Executive, 1998).
Prabhat Krishnaswamy and Richard Lampo, “Recycled-Plastic Lumber Standards: From Waste Plastics to Markets
for Plastic-Lumber Bridges,” Standardization News (December 2001), available online at http://www.astm.org/SNEWS/
DECEMBER_2001/wsd_dec01.html.
26
“Products generated by a business or consumer which have served their intended end uses, and which have been separated
or diverted from solid wastes for the purposes of collection, recycling, and disposition” “RPG Certification,” The Official
Recycled Product Guide (RPG) Web site at http://www.recyclingmarkets.net/products/rpginfo.html.
27
The recycling level for high-density polyethylene milk and water jugs, among the most recycled plastic products in the
nation, hovers at less than 25%. The recycling level for PVC bottles is less than 1%. Other plastic packaging and product
recycling is statistically insignificant. See Peter Anderson, RecycleWorlds Consulting, Message In A Bottle (GrassRoots
Recycling Network, 2004), p. 13, available online at http://www.healthybuilding.net/pvc/PVCBottleRecyclingReport.pdf
28
29
LDPE plastic shopping bags, for instance, can easily be substituted with alternatives such as biodegradable paper bags or
even better, reusable bags. Beverage containers can be offered in refillable plastic bottles, which are the norm in Germany
and other European countries. A 2005 report by the Center for Health, Environment and Justice, Arlington, Virginia, PVC,
Bad News Comes In Threes: The Poison Plastic, Health Hazards & The Looming Waste Crisis highlights the problems with and
alternatives to PVC packaging. This report is available online at http://www.besafenet.com/pvc.htm.
Survey of plastic lumber companies and products conducted by the Healthy Building Network, February 2005. Advanced
Environmental Recycling Technologies (AERT) of Springdale, Arkansas, maker of ChoiceDek wood-plastic composite
decking, reports recycling all scrap left from building with their products. Correct Building Products, LLC, maker of
CorrectDeck wood-plastic composite decking, reports collecting and recycling scraps from installation.
30
The Commonwealth of Massachusetts, Operational Services Division, is one agency that specifies in its procurement
language for recycled plastic equipment that “it is desirable that bidders offer recycling options” for such products. Because
the equipment is still in place, the Division does not know as yet if manufacturers will actually take back their plastic lumber
for recycling. Personal communication, Marcia Deegler, Procurement Team Leader of Environmental Affairs, Operational
Services Division, State of Massachusetts, April 25, 2005.
31
Survey of plastic lumber companies and products conducted by the Healthy Building Network, February 2005. Everlast
Plastic Lumber, Inc., of Auburn, Pennsylvania, maker of Everlast all-plastic lumber, reports selling scrap to a recycled-materials
broker who then sells it to other end processors. RENEW Plastics of Luxemburg, Wisconsin, a division of NEW Plastics
Corporation and maker of Evolve recycled all-plastic lumber, reports it recycles scrap from its dealers. Some of its larger
distributors have secured contracts with manufacturing centers that will accept plastic-lumber scraps.
32
Message in a Bottle: The Impacts of PVC on Plastics Recycling, a report to the GrassRoots Recycling Network by Peter
Anderson, Recycle Worlds Consulting, Madison, Wisconsin (2004), available online at
http://www.healthybuilding.net/pvc/PVCBottleRecyclingReport.pdf
33
25
34
Tiffany Cougar, COO, Everlast Plastic Lumber Co., Auburn, Pennsylvania, personal communication, May 6, 2005.
35
See discussion of synthetic composites.
See William McDonough and Michael Braungart, Cradle to Cradle: Remaking the Way We Make Things (North Point Press,
2003), information available at http://www.mcdonough.com/cradle_to_cradle.htm.
36
U.S. Plastic Lumber Group’s material safety data sheet for its Composite Plastic Lumber, undated. Available online at
http://www.usplasticlumber.com.
37
“Plastics,” Municipal Solid Waste Web site of the U.S. Environmental Protection Agency, http://www.epa.gov/epaoswer/nonhw/muncpl/plastic.htm.
38
“Why Use Recycled Plastic Lumber?” Publication #431-97-009, California Integrated Waste Management Board, Sacramento,
California, March 1997, available online at http://www.ciwmb.ca.gov/plastic/recycled/Lumber.
39
“Product Information, Plastic Lumber, Recycled,” The Commonwealth of Massachusetts Environmentally Preferable
Products Procurement Program Web page at http://www.mass.gov/epp/products/lumber.htm.
40
41
“Decking Serious Alternatives,” Consumer Reports (July 2004), p. 22.
26